Voice over data networks has been seen as the next step in the evolution of wireless voice in cellular communications networks. The preferred protocol for enabling this evolution is Voice over Internet Protocol (VoIP). When using VoIP, each voice frame is routed using an Internet Protocol (IP) header. The IP header for VoIP is considerably larger than the very small header used for transporting voice traffic over the air in traditional 2G/3G cellular communications networks. This implies that the header overhead to payload ratio when using VoIP is much larger than that in traditional 2G/3G cellular communications networks, which is undesirable. One solution to this problem is the use of Robust Header Compression (RoHC) to compress the IP header before the IP header is transmitted over the air.
One key benefit of RoHC when used with VoIP in Long Term Evolution (LTE) cellular communications networks is improved cell coverage for VoIP users. In particular, RoHC decreases the number of bits needed per VoIP packet, thus decreasing the risk that VoIP packet segmentation will occur. This translates into a path-loss improvement, which in turn increases the cell coverage for the VoIP user.
RoHC is a resource intensive application. In other words, RoHC requires a significant amount of resources (i.e., processing cycles and memory) at a base station in a cellular communications network. One issue that arises when using RoHC with VoIP is that the base station may not have sufficient resources to enable RoHC for all VoIP calls. As such, there is a need for systems and methods that selectively enable RoHC for VoIP calls in a cellular communications network.